package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.RedisData;
import com.hmdp.utils.SystemConstants;
import org.springframework.data.geo.*;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;

import java.time.LocalDateTime;
import java.util.*;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import static com.hmdp.utils.RedisConstants.*;
import static com.hmdp.utils.SystemConstants.SHOP_NOT_EXIST;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private CacheClient cacheClient;

    @Override
    public Object queryById(Long id) {
        //空值解决缓存穿透
        //Shop shop = queryWithPassThrough(id);

        //使用工具类解决缓存穿透
        //Shop shop = cacheClient.queryWithPassThrough(CACHE_SHOP_KEY,id,Shop.class,this::getById,CACHE_SHOP_TTL,TimeUnit.MINUTES);

        //互斥锁解决缓存击穿
        //Shop shop = queryWithMutex(id);

        //使用工具类解决缓存击穿
        Shop shop = cacheClient.queryWithLogicalExpire(CACHE_SHOP_KEY,id,Shop.class,this::getById,CACHE_SHOP_TTL,TimeUnit.MINUTES);

        //逻辑过期解决缓存击穿
        //Shop shop = queryWithLogicalExpire(id);

        if (shop == null) {
            return Result.fail(SHOP_NOT_EXIST);
        }
        //7.返回
        return Result.ok(shop);
    }

    //创建线程池，里面有十个独立线程
//    private static final ExecutorService CACHE_REBUILD_EXECUTOR = Executors.newFixedThreadPool(10);
//    public Shop queryWithLogicalExpire(Long id){
//        //1.从redis查询商铺缓存
//        String shopJson = stringRedisTemplate.opsForValue().get(CACHE_SHOP_KEY + id);
//
//        //2.判断是否存在
//        if (BeanUtil.isEmpty(shopJson)) {
//            //3.不存在，直接返回
//            return null;
//        }
//
//        //4.如果命中，需要先把Json反序列化为对象
//        RedisData redisData = JSONUtil.toBean(shopJson, RedisData.class);
//        JSONObject data = (JSONObject)redisData.getData();
//        Shop shop = JSONUtil.toBean(data, Shop.class);
//        LocalDateTime expireTime = redisData.getExpireTime();
//
//        //5.判断是否过期
//        if (expireTime.isAfter(LocalDateTime.now())){
//            //5.1未过期，直接返回店铺信息
//            return shop;
//        }
//
//        //5.2已过期，需要缓存重建
//        //6.缓存重建
//        //6.1获取互斥锁
//        boolean tryLock = tryLock(LOCK_SHOP_KEY + id);
//
//        //6.2判断是否获取锁成功
//        if (tryLock){
//            //6.3成功，开启独立线程，实现缓存重建
//            CACHE_REBUILD_EXECUTOR.submit(() -> {
//                try {
//                    this.saveShop2Redis(id,30L);
//                } catch (Exception e) {
//                    throw new RuntimeException(e);
//                } finally {
//                    //释放锁
//                    unlock(LOCK_SHOP_KEY + id);
//                }
//            });
//        }
//
//        //6.4返回过期的商铺信息
//        return shop;
//    }

//    public Shop queryWithMutex(Long id){
//        //1.从redis查询商铺缓存
//        String shopJson = stringRedisTemplate.opsForValue().get(CACHE_SHOP_KEY + id);
//
//        //2.判断是否存在
//        if (BeanUtil.isNotEmpty(shopJson)) {
//            //3.存在，直接返回
//            Shop shop = JSONUtil.toBean(shopJson, Shop.class);
//            return shop;
//        }
//        //判断命中的是否是空值
//        if (shopJson != null){
//            return null;
//        }
//        //4.实现缓存重建
//        //4.1获取互斥锁
//        Shop shop = null;
//        try {
//            boolean isLock = tryLock(LOCK_SHOP_KEY + id);
//
//            //4.2判断时候获取成功
//            if (!isLock){
//                //4.3失败，则休眠并重试
//                Thread.sleep(50);
//                return queryWithMutex(id);
//            }
//
//            //4.4成功，根据id查询数据库
//            shop = getById(id);
//
//            //5.不存在，返回错误
//            if (shop == null){
//                //将空值写入redis
//                stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY + id,"",CACHE_NULL_SHOP_TTL,TimeUnit.MINUTES);
//                return null;
//            }
//            //6.存在，写入redis
//            stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY + id,JSONUtil.toJsonStr(shop),CACHE_SHOP_TTL, TimeUnit.MINUTES);
//        } catch (InterruptedException e) {
//            throw new RuntimeException(e);
//        } finally {
//            //7.释放互斥锁
//            unlock(LOCK_SHOP_KEY + id);
//        }
//        //8.返回
//        return shop;
//    }
//    public Shop queryWithPassThrough(Long id){
//        //1.从redis查询商铺缓存
//        String shopJson = stringRedisTemplate.opsForValue().get(CACHE_SHOP_KEY + id);
//
//        //2.判断是否存在
//        if (BeanUtil.isNotEmpty(shopJson)) {
//            //3.存在，直接返回
//            Shop shop = JSONUtil.toBean(shopJson, Shop.class);
//            return shop;
//        }
//
//        //判断命中的是否是空值
//        if (shopJson != null){
//            return null;
//        }
//        //4不存在，根据id查询数据库
//        Shop shop = getById(id);
//
//        //5.不存在，返回错误
//        if (shop == null){
//            //将空值写入redis
//            stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY + id,"",CACHE_NULL_SHOP_TTL,TimeUnit.MINUTES);
//            return null;
//        }
//        //6.存在，写入redis
//        stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY + id,JSONUtil.toJsonStr(shop),CACHE_SHOP_TTL, TimeUnit.MINUTES);
//
//        //7.返回
//        return shop;
//    }

//    private boolean tryLock(String key){
//        Boolean flag = stringRedisTemplate.opsForValue().setIfAbsent(key, "1", 10, TimeUnit.SECONDS);
//        return BooleanUtil.isTrue(flag);
//    }
//
//    private void unlock(String key){
//        stringRedisTemplate.delete(key);
//    }

//    //把Shop添加到redis中
//    public void saveShop2Redis(Long id,Long expireSeconds) throws InterruptedException {
//        //1.查询店铺信息
//        Shop shop = getById(id);
//        Thread.sleep(200);
//        //2.封装逻辑过期时间
//        RedisData redisData = new RedisData();
//        redisData.setData(shop);
//        redisData.setExpireTime(LocalDateTime.now().plusSeconds(expireSeconds));
//
//        //3.写入Redis
//        stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY + id,JSONUtil.toJsonStr(redisData));
//    }

    @Override
    @Transactional
    public Result update(Shop shop) {
        Long id = shop.getId();
        if (id == null){
            return Result.fail(SHOP_NOT_EXIST);
        }
        //1.更新数据库
        updateById(shop);

        //2.删除缓存
        stringRedisTemplate.delete(CACHE_SHOP_KEY + id);
        return null;
    }

    @Override
    public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
        //1.判断是否需要根据业务查询
        if (x == null || y == null){
            //不需要坐标查询，按数据库查询
            Page<Shop> page = query()
                    .eq("typeId", typeId)
                    .page(new Page<>(current, System.currentTimeMillis()));
            return Result.ok(page.getRecords());
        }
        //2.计算分页参数
        int from = (current - 1) * SystemConstants.DEFAULT_PAGE_SIZE;
        int end = current * SystemConstants.DEFAULT_PAGE_SIZE;
        //3查询redis，按照距离排序，分页，结果：shopId，distance
        String key = SHOP_GEO_KEY + typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> search = stringRedisTemplate.opsForGeo()
                .radius(key,
                        new Circle(new Point(x,y),new Distance(5000)),
                        RedisGeoCommands.GeoRadiusCommandArgs.newGeoRadiusArgs().includeDistance().limit(end)
                );
        //4.解析出id
        if (search == null){
            return Result.ok(Collections.emptyList());
        }
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> content = search.getContent();
        if (content.size() < from){
            return Result.ok(Collections.emptyList());
        }
        //4.1截取从from到end的部分
        List<Long> ids = new ArrayList<>(content.size());
        Map<String,Distance> distanceMap = new HashMap<>(content.size());
        content.stream().skip(from).forEach(result ->{
            //4.2获取店铺id
            String shopIdStr = result.getContent().getName();
            ids.add(Long.valueOf(shopIdStr));
            //4.3获取距离
            Distance distance = result.getDistance();
            distanceMap.put(shopIdStr,distance);
        });
        //5.根据id查询shop
        String idStr = StrUtil.join(",", ids);
        List<Shop> shops = query().in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list();
        for (Shop shop : shops) {
            shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
        }
        //6.返回
        return Result.ok(shops);
    }


}
